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 areas is accomplished by drilling holes 10 to 12 inches (250 to 300 mm) deep
using a 0.675 inch (17 mm) star drill. The holes should be spaced 2.5 feet
(0.75 m) apart around the perimeter of the screen. Fluted drive pins that
are 12 to 14 inches (300 to 350 mm) long and 0.688 inch (17.5 mm) in diameter
should be driven into the holes and bonded to the screen with pressure
connectors (see figure A-7). After installing the screen, the ground should
be covered with at least 1 inch (25 mm) of sand and should be treated with a
thin layer of magnesium sulphate (epsom salts) and water. It may not be
possible to remove the drive pins once they have been installed. When
installing the screen in sandy soil or in coastal regions, drive pins should
not be used. The screen should be buried approximately 6 inches (150 mm)
below the earth's surface and covered with sand. It should be periodically
treated with magnesium sulphate to ensure an effective ground. All ground
conductors should be bonded to the screen using appropriate pressure
connectors. When drive pins are used and the operation is completed, the
pins should be driven into the ground after the screen is removed.
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